Flake's statement, posted on his Facebook page, is in response to a Public Policy Polling survey that showed his approval rating among Arizona voters at 32 percent.

"Nothing like waking up to a poll saying you're the nation's least popular senator," Flake wrote. "Given the public's dim view of Congress in general, that probably puts me somewhere just below pond scum."

Fifty-two percent said they are less likely to vote for Flake in another election because of his vote on the background check bill.

"Now, notwithstanding the polling firm's leftist bent, I would assume that my poll numbers have indeed taken a southerly turn since my vote against the Manchin-Toomey background check proposal," Flake continued. "It was a popular amendment, and I voted against it."

The junior senator from Arizona also linked to an article by The Arizona Republic's Joanna Allhands which "captures the complexity of the issue" of that gun vote.